From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] ARM: OMAP3: gpmc: add BCH ecc api and modes Date: Wed, 25 Apr 2012 08:58:01 -0700 Message-ID: <20120425155759.GS3739@atomide.com> References: <1334652536-4442-1-git-send-email-ivan.djelic@parrot.com> <1335365341.6356.5.camel@koala> <20120425152310.GR3739@atomide.com> <1335368681.6356.16.camel@koala> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:23243 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755117Ab2DYP6G (ORCPT ); Wed, 25 Apr 2012 11:58:06 -0400 Content-Disposition: inline In-Reply-To: <1335368681.6356.16.camel@koala> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Artem Bityutskiy Cc: linux-omap@vger.kernel.org, linux-mtd@lists.infradead.org, Ivan Djelic * Artem Bityutskiy [120425 08:48]: > On Wed, 2012-04-25 at 08:23 -0700, Tony Lindgren wrote: > > Hi, > > > > * Artem Bityutskiy [120425 07:52]: > > > On Tue, 2012-04-17 at 10:48 +0200, Ivan Djelic wrote: > > > > This patch adds a simple BCH ecc computation api, similar to the > > > > existing Hamming ecc api. It is intended to be used by the MTD layer. > > > > It implements the following features: > > > > > > > > - support 4-bit and 8-bit ecc computation > > > > - do not protect user bytes in spare area, only data area is protected > > > > - ecc for an erased NAND page (0xFFs) is also a sequence of 0xFFs > > > > > > > > This last feature is obtained by adding a constant polynomial to > > > > the hardware computed ecc. It allows to correct bitflips in blank pages > > > > and is extremely useful to support filesystems such as UBIFS, which expect > > > > erased pages to contain only 0xFFs. > > > > > > > > This api has been tested on an OMAP3630 board. > > > > > > > > Signed-off-by: Ivan Djelic > > > > > > Hi Tony, > > > > > > what do you think about merging this patch? This is the enabler for > > > making UBIFS actually usable on OMAP platforms which use BCH ECC. There > > > are 2 other MTD patches which depend on this - so I wonder if it is > > > easier to merge this one via the MTD tree, providing it has your/others' > > > ack(s). > > > > Looks OK to me, however there are other pending GPMC patches to convert > > it to a platform device device driver. Need to look those closer though. > > Anyways, it's best that I queue them to avoid merge conflicts. > > Sure. > > > Do you these for other changes for UBIFS? > > Not in UBIFS, but in drivers/mtd/nand/omap2.c - Ivan sent another patch > which adds BCH support to to omap2.c, was sent to linux-omap, subject > "[PATCH] mtd: nand: omap: add support for hardware BCH ecc" > > > If so, I can set up an immutable > > branch for GPMC that you can merge in as well. > > I guess this would be a good idea, but probably it is better to do this > when you believe you merged most gpmc patches, so probably closer to the > final -rc? Yes let's wait a week or so as there are also the dmaengine patch for drivers/mtd/nand/omap2.c that might conflict. So let's get the dmaengine patches to some branch first. Regards, Tony